(a) For solid ⇌ liquid equilibrium, there is only one temperature at 1 atm at which two phases can co-exist. If there is no exchange of heat with the surroundings, the mass of the two phases remain constant.
(b) For liquid ⇌ vapors equilibrium, the vapors pressure is constant at a given temperature.
(c) For dissolution of solids in liquids, the solubility is constant at a given temperature.
(d) For dissolution of gases in liquids, the concentration of a gas in liquid is proportional to pressure of the gas over the liquid.
